The major objective of this project is to delineate the changes in the lens proteins which occur as a result of the cataractous process. Five specific areas of investigation will be pursued: 1) The delineation of the chemistry of high molecular weight protein and the relationship of its subunits to the low molecular weight soluble protein constituents; 2) The characterization of the chemistry of the water insoluble fraction and the relationship of its polypeptide constituents to other lens protein; 3) An investigation of the contribution to protein transformation and cataract formation of certain post-translational changes such as a) oxidation; b) increased charge heterogeneity and deamidation; c) chain cleavage; d) racemization; e) formation of protein associated fluorescent groups; f) crosslinking reaction involving interchain polypeptide linkage and protein-sugar bonds. 4) The mechanism by which lens polypeptides aggregate to normal sized and HMW and insoluble components. 5) Change in lens fiber membrane structure with development of cataract.